The effects of supplementation of zilpaterol hydrochloride (ZH; 0 or 10 mg/lamb daily) and soybean oil (SBO; 0% or 6%) on carcass traits, body fat deposition, chemical, physicochemical, sensory quality, and fatty acid composition of the longissimus thoracis muscle (LTM) of ewe lambs were studied using a randomised complete design with a 2 × 2 factorial arrangement. After a 32-day feeding period, all ewes were slaughtered and LTM collected. Interactions between ZH × SBO were not observed (P > 0.05) for any of the variables evaluated. Feedlot performance was not modified (P > 0.05) by ZH and SBO supplementation. Biological yield and hot carcass weight were increased by ZH supplementation (P < 0.05). ZH and SBO supplementation did not alter body fat deposition (kidney, pelvic and heart, renal, thickness and intramuscular fat) and the empty bodyweight (P > 0.05). Meanwhile, feeding ZH decreased colour parameters (L*, a*, b* and CHROMA) (P < 0.05), but not others characteristics of LTM (P > 0.05). Sensory panelists observed an increase in appearance (P < 0.001) by ZH supplementation. Additionally, ZH decreased (P < 0.05) the content of C20:5n3 (eicosapentaenoic acid), C22:6n-3 (docosahexaenoic acid) and total omega-3 fatty acids, compared with the zero ZH group. Physicochemicals and sensory characteristics, and fatty acid composition of meat were not modified by SBO (P > 0.05). In conclusion, ZH supplementation to ewe lambs increased biological yield and hot carcass weight, without changes in body fat deposition and decreased eicosapentaenoic acid, docosahexaenoic acid and omega-3 contents and caused a decrease in colour of LTM. However, feeding SBO caused no changes in the carcass or meat quality traits and minimal changes in fatty acid composition of LTM.
Effect of Dietary Polyunsaturated Fatty Acid Concentration on Performance, Fat Deposition, and Carcass Fatty Acid Composition in Broiler Chickens